Slide-fastener stringers for bed linen and the like



A. FRbHLlCH Jan. 20, 1970 NEW AND THE L125:

SLIDE-FASTENER STRINGEFLS FOR BED LI 3 Sheets-Sheet 1 Filed Jan. 22,1968 Alfons Frihlich m VEN TOR A. FRC'JHLICH Jan. 20, 1970 5Sheets-Sheet 2 Filed Jan. 22, 1968 'Asfans Frdhiich [1\ VEN TOR Jan. 20,1970 A. FRCHLICH 3,490,110

SLIDE-FASTENER STRINGERS FOR BED LINEN AND THE LIKE Filed Jan. 22, 19683 Sheets-Sheet 3 Alfons Fr'o'hlich INVENTOR.

Attorney United States Patent 3,490,110 SLlDE-FASTENER STRINGERS FOR BEDLINEN AND THE LIKE Alfons Frtihlich, Essen, Germany, assignor to Opti-Holding A.G., Glarus, Switzerland, a corporation of Switzerland FiledJan. 22, 1968, Ser. No. 699,583 Claims priority, application Germany,Jan. 21, 1967, 0 12,245 Int. Cl. A44b 19/04, 19/22 US. Cl. 24-2051 10Claims ABSTRACT OF THE DISCLOSURE My present invention relates to aslide-fastener stringer for bed linen and other fabric articles of ashrinkable material.

The use of slide fasteners in garments and other fabric articles and inupholstery, pillow covers and the like has had widespread acceptancealthough similar use of closures of this nature has hardly entered thefield of bed linen. It has indeed been proposed to make use of moderntypes of slide fasteners, i.e. closures using continuous couplingelements of meandering or helical configuration on respective supporttapes, but considerable difficulties were presented when conventionalslide fastener stringers where applied to bed linen and the like. Bedlinen is generally characterized by a high cotton content and is for themost part woven so as to withstand rigorous cleaning treatments. Duringfabrication processes, the fabric is treated at elevated temperatures insuch manner as to give rise to a 10% or more shrinkage in the length orWidth of the fabric. Where attempts were made to mount conventionalslide fastener stringers on fabrics for use in contoured sheets,mattress covers, pillow slips and blanket covers, for example, it wasfound that the thermoplastic slide fastener, once stitched in place,produced considerable wrinkling and stressing of the fabric as a resultof such shrinkage.

Moreover, conventional methods of making the slidefastener assemblieshave required that the coupling heads formed on the meandered ribs orthe successive turns of a helicoidal filament be laid in practicallycontacting relationship so that no clearance or play is found betweenthe interengaged head. Only in this manner, has it been possible toinsure a sufficient tight junction between coupling elements and toprovide the necessary transverse strength resisting separation of thecoupling elements.

It is, therefore, the principal object of the present invention toprovide a slide-fastener stringer which is especially suitable for usein bed linen and other fabric articles which may be subjected to highshrinkage phenomena.

Another object of this invention is to provide improved slide-fastenerstringers for fabric articles with relatively high transversed or shearstrength resisting separation of the interengaged coupling elements.

Still another object is to provide an improved method of making aslide-fastener assembly.

I have now found that it is possible to fabricate articles of ashrinkable fabric with slide-fastener stringers whose chains or rows ofcoupling heads are formed from a continuous thermoplastic monofilamentwith an interhead spacing exceeding the normal spacing necessary forproper interfitting of the coupling heads and dimensioned such that,upon shrinkage of the fabric band carrying the coupling elements, thegap between heads is reduced to the desired tolerance for tight fit. Ithas been found, for example, that the slide-fastener stringers for bedlinen and the like can comprise a pair of support or carrying bands ortapes, advantageously composed of a fabric shrinkable to the same extentas that of the bed linen in the direction in which these bands extend,the tapes being provided along their approaching longitudinal edges withcontinuous coupling elements whose heads are spaced upon by an amountexceeding the normal head width but such that, with shrinkage up toabout 10% in the overall length of the band (preferably about 5%shrinkage), the gap between heads is shortened such that the heads ofthe other coupling element are engaged in a tight-fitting manner.

In accordance with a preferred embodiment of this invention, thecoupling elements are-coupled of syntheticresin rnonofilaments (e.g. anylon polyamide) with a filament diameter of 0.2 to about 0.6 mm., theshrinkage step reading to a decrease in a gap width of about 0.1 mm. sothat the overall shrinkage of the coupling chain 0.1 N mm. where N isthe number of coupling heads and the shrinkage is 0.1 mm. per couplinghead. I have chosen the term foreshortening play to indicate the amountby which the interhead width exceeds the width of the head and,therefore, the amount by which each gap must be reduced to bring theheads defining it into tight-fitting engagement with the head of theother coupling element received in this gap.

The present invention is based upon the fact that coupling elements ofthe continuous type, i.e. formed with a continuous chain of couplingheads molded by heat and pressure in the respective turns of acouplingelement coil of thermoplastic synthetic resin, is able to besubjected to elastic deformation in the longitudinal direction becausethe successive turns constitute in effect a coil spring. Thus theshrinkage of the fabric upon which the coils are mounted can be useddirectly or indirectly to condense the coils through the clearance orplay originally provided between the heads, thereby bringing each pairof coupling heads into tight-fitting or hugging engagement with thecoupling head of the opposing element which previously was only looselyreceived in the interhead space. When reference is made hereinafter toan indirect shrinkage effect upon the coupling coils, it will beunderstood that reference is intended to the use of a support band ortape between the coupling elements which, in a direct-action system, aremounted upon the fabric of the article without an intermediate band.When the band is used, however, I prefer to constitute it of ashrinkable material adapted to sustain at least the same degree ofshrinkage as the fabric article to which it is attached. The shrinkageof the band and fabric article, during the usual fabric-handlingtreatments which give rise to such shrinkage in the longitudinaldirection of the coil, mechanically condenses the coil and brings eachcoil into tight-fitting engagement with the heads of the opposing coil.When the fabric-handling treatment involves heat of a sufficient degreeto set the thermoplastic elements, the latter are locked in theirtight-fitting engagement during (i.e. concurrently with) thefabric-handling shrinkage treatment. Thus, within the principles of thepresent invention, the slide-fastener elements may be fixed directly orindirectly along opposite edges of a shrinkage-fabric article (e.g. bedlinen and the like composed of cotton or mixtures of cotton with otherfibers) and need not interfit tightly; the resistance of the slidefastener to separation and its transverse strength are both minimum.When, however, after the fabric article is subjected to its firstwashing, (ie a fabric-handling treatment producing shrinkage), thecoupling heads are drawn together by the fabric shrinkage and hug theheads of the opposing element therebetween.

According to a more specific feature of this invention, the couplingelement is composed of a nylon-type monofilamentary polyamide having acircular cross-section and shaped into generally flat coils whoseopposite longitudinal sides run parallel to the juxtaposed edges of thefabric band or the fabric article upon which the coupling elements aremounted. The coupling heads are formed by plastic deformation (i.e.underheat and pressure) of the turns of the flattened coil along thecorresponding edge as has been described in application Ser. No. 651,757and the host of prior patents dealing with helicoidal and meanderingcoupling chains; to provide the clearance or play between each pair ofheads and the interfitting head of the opposing coupling element, I coilthe circular cross-section monofilament thread with an interturn spacingor pitch in excess of the cross-sectional diameter of the thread orfilament, the amount which the turn spacing exceeds the thread diameterbeing the play.

Alternatively, the longitudinal extent of the deformed portions or headsof the turns may be less than the corresponding gap between the headswhereby th diameter of the receiving portions of the coupling elementsis larger than the length of the coupling surfaces of the coupling headto form thereby the play mentioned earlier. It is possible to provide astructure of this nature by a one-sided deformation of the couplingelements, ie by pressing the flattened turns in the plane of their majordiameters transversely to the longitudinal direction with heat andpressure. The resulting coils may be of pearshaped cross-section. It hasalso been found advantageous to provide coupling elements which arecomposed of monofilamentary threads of thermoplastic synthetic resinwith elliptical or sickle (crescent) shaped configuration, the turnsbeing designed such that the individual coupling heads are inclined inthe longitudinal direction and interengage, the heads being spaced suchthat shrinkage of the engageable slide fastener, upon thefabric-handling treatment discussed earlier, permits the interengagedheads to penetrate deeper into the interhead spaces.

It has been found that a variety of methods can be used effectively tosecure the coupling elements to the fabric article or the support bands,typical methods including stitching, interweaving or interknitting ofthe coupling elements, or simply inserting the coupling heads or turnsthrough a ladderlike array of openings previously formed in the fabricat the spacing of the heads prior to shrinkage. Generally, in the lattercase, the turns will not be materially deformed. It has been observedthat, with shrinkage of the fabric formed with th ladderlike array ofopenings, each turn is positively positioned by the web of materialbetween the openings with the shanks of the flattened coils beingpractically contiguous with one another. When stitching techniques areemployed, double-chain stitches may be used with a single continuousthread row or a plurality of parallel rows, the threads for thestitching operation having a shrinkage corresponding to that of the bandand the article. The shrinkage of the stitching threads can be selectedby proper choice of the yarn and fiber content, by adjustment of thethread tension or by selection of an appropriate spinning or twistingdegree. It has also been found to be important to prevent the shrinkageforce applied by the support band to the fabric articles at a value lessthan that developed by the fabric articles during their own shrinkageprocess. In other words, the shrinkage of the coils should be limited bythe fabric of the article rather than the fabric of the hand. To thisend, I may provide syntheticresin monofilamentary warp threads in theband which limit shrinkage thereof or which are shrinkable to establish,at the temperature of the first fabric treatment subsequent toattachment of the stringer, to a point such that further shrinkage ofthe band is limited at about the shrinkage of the fabric article. Wehave also found it to be highly advantageous to provide the band as aloose Weave or knit mesh which can condense upon shrinkage of the fabricarticle but which is not itself shrunk by the fabric treatment so thatthe band, like the coils, mechanically condenses upon shrinkage of thefabric. This latter arrangement has the significant advantage that asingle stringer may be used on fabric articles with a wide range ofshrinkage potential and on fabric articles of widely differingmaterials. The stringer should be provided with an ironable slider ofthe type described and claimed in my copending application Ser. No.651,757 of July 7, 1967 or my application Ser. No. 698,226 (attorneysdocket No. 5674) filed on or about Jan. 16, 1968 and entitled Sliderwith Cantilevered Guide Formations for Slide-Fastener Closures.

The above and other objects, features and advantages of the presentinvention will become more readily apparent from the followingdescription, reference being made to the accompanying drawing in which:

FIG. 1 is a plan view, somewhat in diagrammatic form, of aslide-fastener stringer in a preliminary stage of manufacture and priorto shrinkage of the fabric article upon which it is provided;

FIG. 2 is a view similar to FIG. 1 showing the stringer after suchshrinkage;

FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 1;

FIG. 4 is a view similar to FIG. 1 of another type of slide-fastenerassembly showing the position of the interengaged coupling elementsprior to shrinkage in solid lines and subsequent to shrinkage indot-dash lines;

FIG. 5 is a cross-sectional view along the lines VV of FIG. 4; and

FIG. 6 is a plan view similar to FIG. 1 showing another embodiment ofthe instant invention.

In my copending applications Ser. No. 619,833 and Ser. No. 624,647,filed Mar. 1, 1967, and Ser. No. 653,402, filed July 14, 1967, l havepointed out the advantages of ladderlike arrays of openings forreceiving the individual heads of a continuous coupling element for aslide-fastener stringer of the general character described above. Inthose applications and in the present case, similar principles areinvolved, namely, the coupling elements are in part anchored in place byshrinkage of a fabric material. In this connection, reference isdirected to FIG. 6 which provides the ladderlike array of openingsanalogous to those illustrated and described in connection withapplication Ser. No. 619,833.

In FIG. 1 of the present case, I show a fabric support comprising a pairof bands la and 1b which represent a shrinkage fabric to which a pair ofcontinuous coupling elements 2 and 3 are attached by parallel rows ofdoublechain stitches 9 whose paths are shown in broken lines in FIG. 1.The stitches are represented in structural terms in FIG. 3. The support1a, 1b may represent the fabric article (e.g. bed linen, pillow slips,etc.) or support tapes which are to be secured to the fabric articlesubsequently as described above. As is apparent from FIG' 1, theinterengageable coupling heads 6a and 6b are formed on respective turnsof a pear-shaped cross-section monofilarnentary synthetic-resin threadby deforming these turns in the direction of arrow A and A under heatand pressure to create lateral protuberances 6a and 61;, respectively.The heads are each located along the outer longitudinal side of theshanks 7a and 7b forming the turns, the shanks being attached to thebands 1a and 112 by the row of double-chain stitches 9 (FIG. 3).

The spacing D between the turns of the coupling elements 2 and 3 exceedsthe diameter d of the monofilamentary material by amounts represented at5 which correspond to the play between each pair of heads of onecoupling element and the head of the other coupling element receivedbetween them. The gaps 4 are designed to amount to up to of the overalllength of the coupling element and preferably about 5% thereof withabout 0.1 mm. per interhead space. Consequently, the interengagedcoupling elements of FIG. 1, prior to shrink age, fit with considerablelooseness. It is desirable, moreover, that the protuberances 6a and 6bproject outwardly from the respective heads in the longitudinaldirection by approximately 0.1 mm. The cross-section of thecoupling-element threads is substantially similar while each turn isdeformed into a pear-shaped cross-section (FIG. 3) such that thediameter of the socket 8 of the coupling members at 4 is greater thanthe length of the coupling protuberances 6a and 6b. The one-sidepressures upon the coupling turns in the direction of arrows A and Acauses an inward bowing of the shanks 7a and 7b of each turn toward oneanother, thereby permitting the diameter of the receptacle 8 to belarger than that possible when the shanks will bend away from oneanother. When the fabric support 10, 1b is subjected to its firstwashing after the attachment of the coupling elements to the fabricarticle, the fabric shrinks substantially (FIG. 2), (preferably about5%) to mechanically condense the couplingelement coils 2 and 3 andthereby provide the tight fit shown in FIG. 2.

In F165. 4 and 5, the coupling elements 12 and 13 are constituted of amonofilamentary resin with generally elliptical or sickle-shaped crosssection (see especially FIG. 5). Here again, the coupling elements maybe attached to a shrinkable fabric support 11a or 11b or to a looselywoven tape or band which is secured to the shrinkable bed linen. Theindividual turns or coupling heads 14 here interfit and are inclinedtoward the longitudinal direction B. The spacing between the couplingheads 14 is so chosen that, with shrinkage of the bands 11a and 11b, thecoupling heads penetrate deeper into the gaps between the coupling headsof the opposing elements by the foreshortening play represented at 15.In FIG. 4, the preshrinkage position of the coupling elements 12 and 13is represented in solid lines while the postshrinkage position is shownby dotdash lines.

FIG. 6 shows another embodiment of this invention wherein the shrinkageof the band 21a and 21b which are to be stitched to the fabric article,is limited by thermally shrinkable warp threads diagrammaticallyillustrated at but constituting the entire warp array. The bands 21a and21b are formed with a ladderlike array of openings 21b through which thecoupling heads 24 of the coils 22 and 23 (see FIGS. 1 and 2) extend. Thecoupling elements are retained in place upon shrinkage of the fabricbands as described in my copending applications Ser. Nos. 619,833 and624,647. Upon shrinkage, the dot-dash position of the coupling elementsis assumed and the foreshortening play is represented at 25. In all ofthe embodiments, one or more rows of double-chain stitches 9 may beprovided to retain the coupling elements upon the band or fabric articleas illustrated in FIGS. 15. The thread tension of these stitches isselected such that they permit shrinkage in step with the fabric. Thebands 1a, 1b, 11a, 11b and 21a, 21b may be loosely woven or knittedcondensable fabric tabs which allow shrinkage of the fabric and thecoupling chains of the bed linen during the initial washing process.When the band is shrinkable (FIG. 6) synthetic-resin monofilamentthreads 10 are provided to limit the total shrinkage of the bandapproximately to the shrinkage of the fabric.

The invention described and illustrated is believed to admit of manymodifications within the ability of persons skilled in the art, all suchmodifications being considered within the spirit and scope of theappended invention.

I claim:

1. A slide-fastener assembly adapted to be mounted upon a shrinkablefabric article and having a shrinkable fabric support and a pair ofinterchangeable continuous coupling elements with a multiplicity ofturns each forming a coupling head receivable between coupling heads ofthe other coup-ling element and compose of a synthetic resin, thecoupling heads of each element being spaced apart to receive thecoupling heads of the other element with a play reducible by shrinkageof said support up to 10% of the length of the coupling elements.

2. The assembly defined in claim 1 wherein the support is a respectivefabric tape carrying each of said coupling elements and attachable tosaid fabric article, said play between each pair of coupling heads beingabout 0.1 mm.

3. The assembly defined in claim 2 wherein said coupling elements arecoils of a thermoplastic monofilament of circular cross-section and saidheads are formations shaped in the successive turns, the spacing betweenthe turns being greater than the diameter of the monofilament to formsaid play.

4. The assembly defined in claim 3 wherein the coils forming saidcoupling elements are generally flattened, said heads being formed byinward deformation of said turns along one longitudinal side of eachflattened coil.

5. The assembly defined in claim 3 wherein said bands are formed withladder arrays of openings at the spacing of said heads and receiving thesuccessive turns of said coupling elements.

6. The assembly defined in claim 3, further comprising respective arraysof stitches securing each of said coupling elements to the respectiveband, said stitches being formed of a shrinkable thread.

7. The assembly defined in claim 3 wherein said bands are formed withwarp threads extending parallel to the respective coupling chains andcomposed of a thermally shrinkable synthetic resin, the extent of theshrinkage threads defining the degree of shrinkage of said couplingelements in the longitudinal direction.

8. The assembly defined in claim 3 wherein said bands are composed of afabric with a shrinkage force less than that of said article.

9. A method of making a slide-fastener assembly for a fabric article upto 10% in at least one direction, comprising the steps of forming a pairof coupling-element coils of thermoplastic monofilamentary syntheticresin with respective coupling heads on each turn of the coilsreceivable between the coupling heads of the other coil and with aninterhead spacing forming with the heads of the opposing coil clearancesof about 0.1 mm.; mounting said coils upon respective support bands of afabric shrinkable in the longitudinal direction by an amount of about10% over the length of the respective coil; securing the respectivebands to the fabric article with the bands and said elements extendingin said direction; and subjecting said article to a fabric treatmentwith said bands secured thereto to shrink the article, said bands andsaid coils, thereby condensing the heads of each coil by said clearance.

10. The method defined in claim 9 wherein said bands and said coils areshrinkable by about 5% in the longitudinal direction, said article beingbed linen, said fabric treatment being the initial washing of the bedlinen subsequent to the securing of said bands thereto.

References Cited UNITED STATES PATENTS 1,724,311 8/ 1929 Prentice.1,848,877 3/1932 Gay 26--1 X 3,354,853 11/1967 Haussmann.

BERNARD A. GELAK, Primary Examiner US. or. X.R.

